Recursive firing pattern algorithm for variable cylinder deactivation in transient operation

Abstract

A cylinder control module generates a desired cylinder activation/deactivation sequence for a future period based on Q predetermined cylinder activation/deactivation sub-sequences used during a previous period, a desired number of cylinders to be activated during a predetermined period including the previous and future periods, and an operating condition. Q is an integer greater than zero. The cylinder control module activates and deactivates opening of intake and exhaust valves of first and second ones of the cylinders that are to be activated and deactivated based on the desired cylinder activation/deactivation sequence, respectively. A fuel control module provides and disables fuel to the first and second ones of the cylinders, respectively.

What is claimed is: 
     
       1. A cylinder control system comprising:
 a cylinder control module that:
 generates a desired cylinder activation/deactivation sequence for cylinders of an engine and for a first predetermined number of crankshaft revolutions using N predetermined cylinder activation/deactivation sub-sequences, each of the N predetermined cylinder activation/deactivation sub-sequences corresponding to a second predetermined number of crankshaft revolutions, wherein N is an integer greater than zero, and the second predetermined number is less than the first predetermined number; 
 activates opening of intake and exhaust valves of first ones of the cylinders that are to be activated based on the desired cylinder activation/deactivation sequence; and 
 deactivates opening of intake and exhaust valves of second ones of the cylinders that are to be deactivated based on the desired cylinder activation/deactivation sequence; and 
 
 a fuel control module that provides fuel to the first ones of the cylinders and that disables fueling to the second ones of the cylinders, 
 wherein the cylinder control module further generates the desired cylinder activation/deactivation sequence for a future period based on a desired number of the cylinders to be activated during a predetermined period, P of the N predetermined cylinder activation/deactivation sub-sequences, and an operating condition, and 
 wherein the future period follows the first predetermined number of crankshaft revolutions, the predetermined period includes the first predetermined number of crankshaft revolutions and the future period, and P is an integer between zero and N, inclusive. 
 
     
     
       2. The cylinder control system of  claim 1  wherein the future period includes at least two future firing/non-firing events. 
     
     
       3. The cylinder control system of  claim 1  wherein P is greater than one. 
     
     
       4. The cylinder control system of  claim 1  wherein the cylinder control module generates the desired cylinder activation/deactivation sequence for the future period based on the desired number of the cylinders to be activated during the predetermined period, P of the N predetermined cylinder activation/deactivation sub-sequences, and an engine speed. 
     
     
       5. The cylinder control system of  claim 1  wherein the cylinder control module generates the desired cylinder activation/deactivation sequence for the future period based on the desired number of the cylinders to be activated during the predetermined period, P of the N predetermined cylinder activation/deactivation sub-sequences, and an engine torque request. 
     
     
       6. The cylinder control system of  claim 1  wherein the desired number of the cylinders to be activated during the predetermined period is an integer. 
     
     
       7. The cylinder control system of  claim 1  wherein the cylinder control module generates the desired cylinder activation/deactivation sequence for the future period further based on predetermined percentages associated with predetermined cylinder activation/deactivation sub-sequences, respectively. 
     
     
       8. The cylinder control system of  claim 1  wherein the cylinder control module generates the desired cylinder activation/deactivation sequence for the future period using predetermined cylinder activation/deactivation sub-sequences stored in memory. 
     
     
       9. The cylinder control system of  claim 8  wherein the cylinder control module selects from the predetermined cylinder activation/deactivation sub-sequences based on the desired number of the cylinders to be activated during the predetermined period, the P of the N predetermined cylinder activation/deactivation sub-sequences, and the operating condition. 
     
     
       10. The cylinder control system of  claim 1  wherein the cylinder control module generates the desired cylinder activation/deactivation sequence for the future period based on noise and vibration. 
     
     
       11. A cylinder control system comprising:
 a cylinder control module that:
 generates a desired cylinder activation/deactivation sequence for a future period based on Q predetermined cylinder activation/deactivation sub-sequences used during a previous period, a desired number of cylinders to be activated during a predetermined period including the previous and future periods, and an operating condition, 
 wherein Q is an integer greater than zero; 
 activates opening of intake and exhaust valves of first ones of the cylinders that are to be activated based on the desired cylinder activation/deactivation sequence; and 
 deactivates opening of intake and exhaust valves of second ones of the cylinders that are to be deactivated based on the desired cylinder activation/deactivation sequence; and 
 
 a fuel control module that provides fuel to the first ones of the cylinders and that disables fueling to the second ones of the cylinders. 
 
     
     
       12. A cylinder control method comprising:
 generating a desired cylinder activation/deactivation sequence for cylinders of an engine and for a first predetermined number of crankshaft revolutions using N predetermined cylinder activation/deactivation sub-sequences, each of the N predetermined cylinder activation/deactivation sub-sequences corresponding to a second predetermined number of crankshaft revolutions, wherein N is an integer greater than zero, and the second predetermined number is less than the first predetermined number; 
 activating opening of intake and exhaust valves of first ones of the cylinders that are to be activated based on the desired cylinder activation/deactivation sequence; 
 deactivating opening of intake and exhaust valves of second ones of the cylinders that are to be deactivated based on the desired cylinder activation/deactivation sequence; 
 providing fuel to the first ones of the cylinders; 
 disabling fueling to the second ones of the cylinders; and 
 generating the desired cylinder activation/deactivation sequence for a future period based on a desired number of the cylinders to be activated during a predetermined period, P of the N predetermined cylinder activation/deactivation sub-sequences, and an operating condition, 
 wherein the future period follows the first predetermined number of crankshaft revolutions, the predetermined period includes the first predetermined number of crankshaft revolutions and the future period, and P is an integer between zero and N, inclusive. 
 
     
     
       13. The cylinder control method of  claim 12  wherein the future period includes at least two future firing/non-firing events. 
     
     
       14. The cylinder control method of  claim 12  further comprising generating the desired cylinder activation/deactivation sequence for the future period based on the desired number of the cylinders to be activated during the predetermined period, P of the N predetermined cylinder activation/deactivation sub-sequences, and an engine speed. 
     
     
       15. The cylinder control method of  claim 12  further comprising generating the desired cylinder activation/deactivation sequence for the future period based on the desired number of the cylinders to be activated during the predetermined period, P of the N predetermined cylinder activation/deactivation sub-sequences, and an engine torque request. 
     
     
       16. The cylinder control method of  claim 12  wherein the desired number of the cylinders to be activated during the predetermined period is an integer. 
     
     
       17. The cylinder control method of  claim 12  further comprising generating the desired cylinder activation/deactivation sequence for the future period further based on predetermined percentages associated with predetermined cylinder activation/deactivation sub-sequences, respectively. 
     
     
       18. The cylinder control method of  claim 12  further comprising generating the desired cylinder activation/deactivation sequence for the future period using predetermined cylinder activation/deactivation sub-sequences stored in memory. 
     
     
       19. The cylinder control method of  claim 18  further comprising selecting from the predetermined cylinder activation/deactivation sub-sequences based on the desired number of the cylinders to be activated during the predetermined period, the P of the N predetermined cylinder activation/deactivation sub-sequences, and the operating condition. 
     
     
       20. The cylinder control method of  claim 12  further comprising generating the desired cylinder activation/deactivation sequence for the future period based on noise and vibration.